/* Calculator CSS format */

  .calculator-grid {
    display: grid;
    align-content: center;
    justify-content: center;
    min-height: 50vh;
    grid-template-columns: repeat(4, 100px);
    grid-template-rows: minmax(auto) repeat(5, 100px);
    }

    .calculator-grid > button {
      cursor: pointer;
      font-size: 2rem;
      border: 1px solid #FFFFFF;
      outline: focus;     
    }

      .calculator-grid > button:hover {
        background-color: #a9a9a9;
      }

      .span-two {
        grid-column: span 2;
        color: #adf802;
        background-color: rgba(139, 0, 139, 0.8);
      }

      .output{
        grid-column: 1 / -1;
        background-color: rgba(0, 0, 0, 0.75);
        display: flex;
        align-items: flex-end;
        justify-content: space-around;
        flex-direction: column;
        padding: 25px;
        word-wrap: break-word;
        word-break: break-all;
      }

      .output .previous-operand{
        color: rgba(255,255, 255, 0.75);
        font-size: 1.5rem;
      }

      .output .current-operand{
        color: white;
        font-size: 2.5rem;
      }